Topic/Type: 1.2 Fusion Plasmas (magnetic & inertial confinement), Poster

Numerical techniques for large-scale PIC simulations of fast ignition

F. Fiuza1, R. A. Fonseca1, L. O. Silva1, J. Tonge2, J. May2, W. B. Mori2, 3

1 GoLP/IPFN, Instituto Superior T?cnico, Lisboa, Portugal
2 Department of Physics & Astronomy, University of California, Los Angeles, CA 90095
3 Department of Electrical Engineering, University of California, Los Angeles, CA 90095

One of the critical issues for fast ignition of fusion targets is to understand and optimize the coupling of the ignition laser to the fast particles, and the transport of the accelerated particles in the mildly to high dense region of the target. Particle-in-cell (PIC) simulations are one the main tools capable of providing a self-consistent modeling of such highly nonlinear phenomena. However, the extreme densities and temperatures present in a fast ignition target pose several numerical constrains, in particular due to under-resolution of the Debye length, requiring advanced numerical techniques in order to allow for an accurate modeling.
We will describe some of the recent numerical techniques developed in the PIC code OSIRIS to improve energy conservation at the extreme conditions of fast ignition, as higher-order particles shapes and current and field smoothing. We have performed a series of simulations in order to understand the importance of these techniques in the modeling of the transport of hot-electrons in the mildly to high density region of a fast ignition target.
Our results demonstrate that the use of these advanced techniques are crucial in order to obtain an accurate modeling. Furthermore, the improved performance obtained using these techniques, associated with the use of single precision allows for large computational time savings, opening the way towards large-scale modeling of fast ignition with PIC simulations.